I think that Payflow Link has the shopper leave your site and go to pay on a website provided by PayPal while Payflow Pro keeps the shopper on your site while they are paying. Do not worry about the Payflow Link product requiring the customer to sign up with PayPal, it does not work like that, it's strictly a payment page where they put in their information, there is no requirement to create an account or other ties to traditional PayPal payments.
payment gateways